The novella The Shattered World Within (published in Giganotosaurus Feb, 2013), describes how the characters find an odd planet:
The seventh planet was perhaps the oddest of all. This planet, too, was a gas giant, blue-purple in colour, with a wide system of pretty rings. It had thirty-five moons, all of them either too small for a colony or too dangerously close to the rings. Many had erratic orbits. The planet described an elliptical orbit perpendicular to the plane of the ecliptic. And it moved backwards, spinning rapidly. More oddly, when the crew obtained a higher magnification scan, it showed that the planet wasn’t circular; it was more like a coagulating cloud.
This story, set in my space opera world, takes place about 100 years before the present. The world “discovered” in the story is the weird and wonderful world of Hedron. Long ago, it was a nice, green planet in the habitable zone, when a rogue wandering planet knocked it out of orbit. Sunlight has vanished in the cloud of gas and debris. Vegetation has fossilised or vanished. Some life still exists underground.
How long would it take for and Earth-like planet to lose habitability
– if it remained cloaked in an insulating cloud
– if it had a molten core
– if a chemical process supplemented oxygen (yay, space opera here, so I can wave my hands as much as I want)
The philosophy about Hedron is that sometimes the universe throws us really weird curveballs. Things–like life–exist in places where by rights they shouldn’t.
Today’s Hedron has a dead and cold surface, but not cold enough for the atmosphere to freeze out. It has retains breathable air and an atmosphere. This far from the sun, and hidden behind clouds of gas and rubbish, the surface sees little sunlight. The planet itself is rich in metals. The planet’s atmospheric composition and orbit are probably not stable. But stable enough for people to live (and hide) there for a good period of time, give or take a couple of thousand years.
The people who settled there 100 years ago, as described in The Shattered World Within, were rebels and outcasts from Asto. Within a few “years” (year is a rather useless term of time measurement, because it’s well over 200 Earth years), these people got their act together and started a mining venture. It has a weird system of government, where the board of the mining company is also the government, but where all residents are shareholders and as such, can’t sacked. Casual observers will find a fair number of features of the system resembling communism, whereas the society presents a commercial face in other aspects.
Hedron has been mentioned in almost every Aghyrians story, but I’ve never set anything there. The main character from Soldier’s Duty, Izramith Ezmi, is from Hedron. She has never seen sunshine, or any vegetation that is not artificially grown. She has never seen houses in the open air, or streets, or any of the things that we see when we look out the window.